Random assignment is a way to place participants into groups by chance. It helps researchers make fair comparisons and strengthens the case that observed differences are due to an experimental treatment rather than preexisting differences among participants.
Random assignment, also called random placement, uses a chance-based procedure to assign participants or animal subjects to groups, such as a treatment group and a control group. A researcher might flip a coin for each participant or use a random number generator.
All flashcards
Random assignment
Using chance to allocate participants or subjects to experimental groups.
Random sampling
Selecting participants from a population to help obtain a representative sample.
Confounder
A factor that provides an alternative explanation for an observed relationship between treatment and outcome.
Chance imbalance
A group difference that occurs by chance despite random assignment.
Peirce's contribution to randomization
Charles S. Peirce emphasized randomization in statistical inference and used it in a weight-perception experiment.
Quiz questions
A statistical test finds a significant difference between two randomly assigned groups. What does that result establish about the allocation?Answer: It does not establish that allocation was nonrandom; the difference may be unlikely under the tested null model.
What is the main distinction between random sampling and random assignment?Answer: Sampling concerns who enters a study; assignment concerns which experimental group each participant enters.
Which statement best describes what random assignment can guarantee about starting group characteristics?Answer: It cannot guarantee identical groups, because chance differences may remain.
Which combination can add safeguards to a randomized controlled trial?Answer: Blinding and placebo control.
Based on the Wikipedia article Random assignment, licensed CC BY-SA 4.0. Adapted into a summary, flashcards and quizzes.